One of the ways to separate macromolecules such as proteins, nucleic acids, charged sugars and peptides etc. is through electrophoresis wherein, electrical voltage is applied to the moities to be separated and these move with different velocities in a solution depending upon their charge, size, shape and viscosity of the medium. To disallow diffusion of the macromolecules in solution due to convection currents, the solution is supported on a porous matrix.
A number of such matrices are available (Davis, M. G. 1986. Electrophoretic techniques. In A biologists guide to principles and techniques of practical biochemistry. (Wilson, K. and Goulding, K. H., eds.) 3rd Ed. English Language Book Society/Edward Arnold. London. pp. 245-268; Plummer, D. T. 1988. An introduction to practical biochemistry. 3rd Ed. Tata McGraw-Hill Publishing Company Limited, New Delhi, 332p). These include (a) paper, (b) cellulose acetate strip, (c) cellulose, silica, kieselguhr or alumina layered on a glass plate, and (d) various types of gel matrices. Gel as a supporting medium is a medium of choice in protein and nucleic acid research. This includes gels made from (a) starch, (b) agar (a mixture of agarose and agaropectin; dissolved by heating in a buffer medium to get the porous matrix), (c) agarose (a polymer of D-galactose and 3,6-anhydro L-galactose; dissolved by heating in a buffer medium to get the porous matrix), and (d) polyacrylamide.
Normally, agarose gel is a matrix of choice while working with nucleic acids. One of the requirements of working with nucleic acid is to transfer the separated nucleic acid from the gel matrix onto a membrane in a blotter. The blotter is an apparatus wherein the nucleic acids or the like are transferred from the gel onto the membrane. In a vacuum blotter, the process of transfer is assisted with the help of vacuum. This constitutes one of the most important steps of southern or northern blotting.
In southern blotting, deoxyribonucleic acid (hereinafter known as DNA) is digested with endonucleases followed by electrophoretic separation of the digested fragments on agarose gel and finally transfer of the digested DNA onto a membrane. To ease transfer of large-sized DNA from the gel onto the membrane, DNA strands need to be (i) cleaved using 0.25 M hydrochloric acid, (ii) denatured using 1.5 N sodium chloride/0.5 N sodium hydroxide to obtain single strand, and (iii) neutralized using 1.5 N sodium chloride/0.5 N tris-chloride (pH, 7.0) to allow proper binding of DNA onto the membrane onto which the transfer has to take place. After achieving these steps of processing, the gel needs to be placed onto a membrane to allow transfer of DNA from the gel onto the membrane (Ausubel, F. M., Brent, R., Kingston, R. E., Moore, D. D., Seidman, J. G., Smith, J. A. and Struhl, K. 1998. Current protocols in molecular biology. John Wiley & Sons, Inc. New York, pp. 2.8.1-2.9.15).
In northern blotting, ribonucleic acid (hereinafter known as RNA) is run on agarose gel that usually contains formaldehyde. For efficient transfer of RNA from the gel onto the membrane, RNA containing gel needs to be (i) washed several times with water, (ii) denatured using 1.5 N sodium chloride/0.05 N sodium hydroxide, (iii) neutralized using 1.5 N sodium chloride/0.5 N tris-chloride (pH, 7.4), (iv) soaked in 20×SSC (3 M sodium chloride, 0.3 M sodium citrate; adjust pH to 7.0 with 1 M hydrochloric acid). After achieving these steps of processing, the gel needs to be placed onto a membrane to allow transfer of RNA from the gel onto the membrane (Ausubel, F. M., Brent, R., Kingston, R. E., Moore, D. D., Seidman, J. G., Smith, J. A. and Struhl, K. 1998. Current protocols in molecular biology. John Wiley & Sons, Inc. New York, pp. 4.9.1-4.9.16).
These processes are normally carried out in containers which are normally baking dish or in plastic box (Sambrook, J., Fritsch, E. F. and Maniatis T. 1989. Molecular cloning: A laboratory manual. 2nd Ed. Cold Spring Harbour Laboratory Press. New York; Ausubel, F. M., Brent, R., Kingston, R. E., Moore, D. D., Seidman, J. G., Smith, J. A. and Struhl, K. 1998. Current protocols in molecular biology. John Wiley & Sons, Inc. New York). While changing various solutions as mentioned in the above paragraph, the container is tilted to remove the solution. The gel needs to be held by hand to avoid falling of the gel along with the solution. Secondly, after giving various washes with different solutions as mentioned in the above paragraph, the gel has to taken out from the container to be placed over the membrane. This second process leads to the damage of the delicate gel. Also, the gel has to be placed onto the membrane properly and once kept onto the membrane, the gel can not be moved.
As recognized herein, the agarose gel holding precious samples of DNA or RNA is delicate and fragile, and liable to damage during various steps mentioned above. The risk of damage increases with increase in the size of the gel. Particularly, during the processing of large number of samples, the size of the gel may be as big as, but not limited to, measuring 15×22 centimeter (width×length).
This dictates the development of a gel processing and transfer device that ensures intact gel during various processes as described above.
Also, while working with proteins, the staining of the proteins requires several solutions to be changed one after another and once the proteins are stained, the photography of the gel is essential to record the data (Hames, B. D. 1990. One dimensional polyacrylamide gel electrophoresis. In Gel electrophoresis of proteins: A practical approach. (Hames, B. D. and Rickwood, D., eds.) 2nd Ed. IRL Press at Oxford University Press, Oxford. pp. 1-147). This also dictates the development of such device, wherein intactness of the gel should be ensured during staining protocols and the device should be capable of presenting the gel for the purpose of photography.
Such a device could not be found with various firms dealing with laboratory products. The catalogue of the following firms were scanned:                (a) Fisher Scientific, 585 Alpha Dr., Pittsburgh, Pa., 15205-9913, USA.        (b) Cole-Parmer, Instrument company, 625 East Bunker Court, Vernon Hills, Ill. 60061-1844. USA.        (c) Becton Dickinson Labware, Two Oak Park, Bedford, Mass. 01730-9902, USA.        (d) Amersham Pharmacia Biotech UK Ltd., Amersham Place, Little Chalfont, Buckinghamshire, HP7 9NA, England.        (e) Brand GMBH+CO KG, Laboratory Equipment Manufactures, P. O. Box 1155 D-97861 Wertheim Germany.        (f) Sigma Chemical Co. P. O. Box 14508 St. Louis, Mo. 63178 USA.        (g) Gibco BRL Life Technologies 9880 Medical Centre Drive P. O. Box 6482 Rockville, Md. 20849-648.        (h) Consort Ltd. Parklaan 36 B-2300 Turnhout, Belgium.        (i) Bio-Rad Laboratories 2000 Alfred Nobel Drive, Hercules, Calif. 94547.        (j) S. D. Fine-Chem Ltd. 315-317, T.V. Industrial Estate, 248 Worli Road, Mumbai 400025 India.        (k) Tarsons Products Pvt. Ltd. 856 Marshell House, 33/1 Netaji Subash Road, Calcutta 700001 India.        (l) Imperial Bio-Medics, Show Room No. 36, Sector-26, Madhya Marg, Chandigarh 160019 India.        (m) Bangalore Genei Pvt. Ltd., No. 6, 6th Main, BDA Industrial Suburb, Near SRS Road, Peenya, Bangalore 560058 India.        
Product number Z 35,829-0 and Z 35,830-4 by M/s Sigma Chemical Co, USA and product number 482030 by M/s Tarsons Products Pvt. Ltd., India describe a gel staining tray. However, the product is basically a plastic box structure with an outlet at the base and has the following shortcomings:                1. The product can accommodate a limited-sized gel        2. The gel is broken during transfer from the product onto a blotter        
Since the Product number Z 35,829-0 and Z 35,830-4 by M/s Sigma Chemical Co, USA is also similar to the one by M/s. Tarsons Products Pvt. Ltd., India (product number 482030) apart from the size, end result is likely to be the same.)
Thus, there is no gel processing and transfer device that ensures intact gel (i) during various processes that are involved after electrophoresis of nucleic acids and before placing the gel onto the membrane for the purpose of transfer of nucleic acid, and (ii) during transfer of the gel from the device onto the membrane. The patent search has been conducted to survey the existing patents relating to the use of processing and transfer of gels. The critical study of the prior patents indicates that none of them is, somehow, not at all connected to the type of applications the present invention is intended to. A new device which is being planned to be launched by the applicant would be a service through which users would be accessed to a device which will help processing and transfer of gels with minimal handling. This object of invention would be the first of its kind.